Hi All,
         I am using ajax in one of my web application. Sometimes I am getting the following error

 "Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation".

I am getting this kind of error sometimes when i click on a dropdown control.

Can any one please tell me what is the reason for this error & how to solve it. Many forums suggested to turn "EnableEventValidation=false". But I think this is only a temporary solution. Can any please provide me the permanent solution for this and what could be the reason for this kind of error.